Evaluate the differentiation of sensory receptors within the pharyngeal complex in embryonic newborn, and one to two month old rhesus monkeys, using both light and electron microscopic techniques. Study, as available, mucosal and skin receptors in embryonic and fetal human specimens (obtained at therapeutic hysterectomy), and in neonatal and young infants up to three months of age, with a view to characterizing; according to stage of development, the sensory receptors in these tissues.